Port UnderscoresToCamelCase logic from protobuf java compiler

[hpuac]

In some edge cases the generated names did not match the java names.
This fixes issue #115

[codecov]

Codecov Report

Merging #118 (0573465) into master (2b0b447) will decrease coverage by 1.35%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #118      +/-   ##
============================================
- Coverage     88.61%   87.26%   -1.36%     
  Complexity       21       21              
============================================
  Files            16       16              
  Lines           369      369              
  Branches         50       50              
============================================
- Hits            327      322       -5     
- Misses           25       26       +1     
- Partials         17       21       +4     

Impacted Files	Coverage Δ	Complexity Δ
...oferrer/krotoplus/coroutines/server/ServerCalls.kt	87.20% <0.00%> (-3.49%)	0.00% <0.00%> (ø%)
...rcoferrer/krotoplus/coroutines/call/FlowControl.kt	72.91% <0.00%> (-2.09%)	0.00% <0.00%> (ø%)
...oferrer/krotoplus/coroutines/client/ClientCalls.kt	89.09% <0.00%> (-1.82%)	0.00% <0.00%> (ø%)

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